The aim of the study is to show an improvement of quality of life on the 5th week of product consumption (probiotic Lactobacillus paracasei LP-33)(as assessed by RQLQ global score) in subjects with persistent allergic rhinitis currently treated with Loratadine or oral anti-histaminic treatment.

Oral H1-antihistamines are first treatment recommended for allergic rhinitis (Bousquet et al, 2008) however they do not completely alleviate symptoms. This new study will therefore assess the effect of Lactobacillus paracasei LP-33 in the management of nasal and ocular symptoms, in addition to H1-antihistamines treatment. The main objective is to evaluate the effect of Lactobacillus paracasei LP-33 on quality of life. Additionally allergic rhinitis symptoms (nasal and eye symptoms) and immunological parameters will be evaluated, before and during the supplementation. Lactobacillus paracasei LP-33 is targeting the general population and improving quality of life of people sensitized to allergens. The study will be conducted in Europe on adult subjects with persistent allergic rhinitis.

Inclusion Criteria:

• Male and female subjects;
• Aged 18 to 60 years;
• People with nasal and ocular discomfort at least sensitized to grass pollen;
• Subject with PER allergy (persistent form) as defined by ARIA guidelines or with a recurrent history of seasonal allergic rhinitis documented by treatment intakes in his medical dossier.
• Previous positive skin prick test or presence of specific serum IgE antibodies class II or above against timothy grass in the last 5 years. If no data are available, a test for detection of timothy grass specific serum IgE antibodies (Phadia CAP System) will be performed at the pre-inclusion visit;
• With RQLQ score ≥ 2;
• Subjects agree to stop consumption of probiotics (food or dietary supplement containing probiotics) and vitamins and/or minerals during the study (D-10/D-7 to D49).

Female subjects with efficient contraception and asthmatic subjects (with a controlled disease and without oral corticosteroid) can be included in the study.

The baseline period prior to treatment with Lactobacillus paracasei LP-33 is 7 days. On recommendations of the consulted experts, Pr Bousquet and Pr Hamelmann, a wash-out period of 3 additional days is recommended before baseline for subject using intranasal corticosteroid before their inclusion. As a consequence, the baseline may be extended to 10 days for these subjects In case the subject consumed an anti-H1 (other than Loratadine) before his (her) inclusion, he (she) will have to switch to Loratadine to be included.

Exclusion Criteria:

• Taking part in another clinical trial or being in the exclusion period of a previous clinical trial;

  • Presenting a psychological incapability or having a bad comprehension of the language (French or German according to the concerned country) to understand the information letter and then to sign the informed consent;
  • Refusing to sign the informed consent;
  • Adult under legal protection (guardianship, wardship) or deprived from his rights following administrative or judicial decision;
  • Pregnant or breastfeeding women;
  • Use of medication which could interfere with the study in the investigator's opinion (antibiotics, etc…);
  • Subject who does not agree to stop his/her consumption of dietary supplements and foods containing probiotics and his/her supplementation of vitamins/minerals during the study (D-10/D-7 to D49).